The final cost of a bookstore purchase with a $5 coupon in a state that charges 8% sales tax is given by this expression. The variable x represents the amount of the purchase before the sales tax and the coupon is applied. 1.08 ( x-5 )

What does ( x-5 )represent?

a.) the total charge before applying sales tax
b.) the rate at which the total cost increases
c.) The cost before applying the coupon
d.) the total charge after tax